Mobility communications system

ABSTRACT

A method of wireless communication includes establishing a wireless connection with a first access point via a wireless protocol in a first sub-network by a wireless electronic device. A network address is assigned to the wireless electronic device having a telephone address. The wireless electronic device roams from the first sub-network to a second sub-network. The wireless connection is automatically disconnected with the first access point, and the wireless connection is seamlessly established with a second access point in the second sub-network. A new network address is assigned to the wireless electronic device at the second sub-network. Alternatively the network address is still assigned to the wireless electronic device at the second sub-network.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] Embodiments of the present invention relate to wireless networkcommunication systems. More particularly, embodiments of the presentinvention relate to wireless network communication systems that supportsecured seamless roaming of real-time voice and data communicationssessions utilizing portable wireless electronic devices.

[0003] 2. Discussion of the Related Art

[0004] Not long ago, discrete technologies had discrete purposes.Telephones made calls, office-bound computers accessed databases, andpersonal digital assistants (PDAs) were simple scheduling devices. Butthe changing, and increasingly mobile, needs of business dictated a newstrategy: convergence of business communications technologies into aflexible array of services that can be accessed through the enterpriseand beyond, by almost any device.

[0005] Therefore, mobile computing has become more prevalent. In recentyears, there has been an increase in the deployment of notebook personalcomputers (notebook PCs) and PDAs. This deployment is a result of theincreasing need for users to be productive in places other than in theoffice or behind the desk. Companies are requiring more work to beaccomplished with less people. Productivity increases are a key metricfor wireless return on investment (ROI). Virtual private networks (VPNs)and wired and wireless modems permit secured access to corporate dataoutside of the office. And, deployments of wireless local area networks(W-LANs) are also increasing in schools and corporate campuses.

[0006] Public W-LANs are emerging as a viable alternative tocircuit-switched or packet-switched cellular data connections. Moreover,the convergence of voice and data on the LAN is rapidly occurring.Several companies are pushing toward the widespread adoption of InternetProtocol (IP) telephony. Many intra-offices and intra-enterprises arenow migrating from traditional circuit-switched solutions to trafficthat are transported and switched as packets or cells. Moreover, thestandards governing Voice over IP (VoIP), such as H.323, SessionInitiation Protocol (SIP), Power over Ethernet (or Power over LAN), forexample, are being finalized and established, which further promotesacceptance and adoption of packet-based communications.

[0007] Personal computers (PCs), PDAs, and other devices are managingmore voice and multi-media communications. More telephones are connectedto data networks, or LANs, so that in addition to making calls, they canaccess directories, messaging, and other database information. Whetherin and around the office or campus, at home, or somewhere in between,being connected to these voice, data, and other multimedia resources iscritical to meeting the new business demands for productivity andresponsiveness.

[0008] Accordingly, it is desirable to have a wireless communicationssystem capable of interacting with a voice network, such as a privatebranch exchange (PBX), and a data network, such as a LAN or Internet, toprovide users with secured seamless mobile access to the same resourcesthey would otherwise have at their desks while roaming throughout acommunity, such as an office or school campus.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 illustrates a mobility communications system according toan embodiment of the present invention.

DETAILED DESCRIPTION

[0010]FIG. 1 illustrates a mobility communications system according toan embodiment of the present invention. A local area network (LAN)backbone 110 provides connectivity between the various components of themobility communications system 100. At the heart of the mobilitycommunications system 100 is the mobility communications system (MCS)server 140, which provides main control over the entire system 100. Aprivate branch exchange (PBX) system 120, such as the Toshiba™Strata-CTX system, is connected to a public switched telephone network102. The PBX system 120 may also have a connection with a time divisionmultiplexing (TDM) network 104 (also known as digital leased lines). Agateway 130, such as a Cisco™ 2600 intelligent media gateway,interconnects the PBX system 120 and the LAN backbone 110. The gateway130 is a liaison to permit communications between two protocols, forexample, between the PBX protocol and the Internet Protocol (IP).

[0011] The mobility communications system 100 is connected to a widearea network (WAN), such as the Internet 106, via a router 150 and afirewall 152. A virtual private network (VPN) server 148 may be includedin the mobility communications system 100 to provide security andencryption/decryption capabilities to the system 100 utilizing, forexample, the IP Security (IPSec) protocol. A remote authenticationdial-in user service (RADIUS) server 156 may be included in the mobilitycommunications system 100 to provide authentication and accounting ofusers of the system 100. Other authentication protocols and serversystems may be implemented as well, and integration with otherauthentication protocols, such as the Diameter protocol for example, maybe implemented. Furthermore, a domain server 154 may be included in themobility communications system 100 to facilitate access to and from theWAN, such as the Internet 106.

[0012] An applications server 142 may be included in the mobilitycommunications system 100 to store and provide applications to thesystem 100. A database server 144 may also be included in the mobilitycommunications system 100 to provide database storage and functionalityto the system 100. A dynamic host configuration protocol (DHCP) and/or adynamic rapid configuration protocol (DRCP) server 146 is connected tothe LAN backbone 110 to assign IP addresses to the nodes of the network.

[0013] A plurality of wireless electronic devices 10, 20, 30, 40communicate wirelessly with the mobility communication system 100 via awireless protocol. The wireless electronic devices 10, 20, 30, 40communicate wirelessly with access points 191, 192, 193, 194, which arepreferably radio frequency (RF) transceivers, for example, and which arein communication with a node server 181, 182 via a switch 171, 172. Theswitch 171, 172 may be connected to a router 160, which is connected tothe LAN backbone 110. The switch 171, first node server 181, accesspoints 191, 193, and wireless electronic devices 10, 20 (before roaming)form a first sub-network, or virtual local area network (VLAN 1). Theswitch 172, second node server 182, access points 192, 194, and wirelesselectronic devices 20 (after roaming), 30, 40 form a second sub-network,or virtual local area network (VLAN 2).

[0014] Each wireless electronic device 10, 20, 30, 40 is authenticated,accounted, and authorized by the MCS server 140, which relays thisinformation (e.g., via certificates) to the first node server 181 andthe second node server 182. Accordingly, when a wireless electronicdevice 20 moves/roams from one sub-network to another, the wirelesselectronic device 20 need only communicate and re-authenticate with thecorresponding first node server 181 or second node server 182, and thecommunication path need not go back to the MCS server 140 across the LANbackbone 110. The Protocol for carrying Authentication for NetworkAccess (PANA), may be utilized to provide authentication, accounting,and authorization (AAA) to authenticate clients (i.e., wirelesselectronic devices) when they roam. PANA is a Layer 3 networkauthentication protocol that supports secure authentication overwireless connections. PANA supports seamless roaming betweensub-networks and between W-LAN and cellular packet-based networks aswell.

[0015] The wireless electronic device 20, for example, establishes awireless connection with an access point 193 in the first sub-network.Accordingly, the wireless electronic device 20 is provided with accessto the mobility communications system 100 network and all its resources,including access to the Internet 106 and the PBX system 120. Accordingto an embodiment of the present invention, the wireless electronicdevice 20 is adapted to function as a wireless telephone having atelephone address or number (or a PBX extension number). The wirelesselectronic device 20 is capable of accessing all of the PBXfunctionality of the PBX system 120 as if it was a hardwired telephone,including voice mail, conference calling, call waiting, callforwarding/transferring, directory look-up, etc. Moreover, the wirelesselectronic device 20 may also be adapted to function like a desktopcomputer connected to the corporate LAN, including access to theInternet 106, and available software applications.

[0016] According to an embodiment of the present invention, the wirelesselectronic devices 10, 20, 30, 40 utilize the Session InitiationProtocol-Mobile (SIP-M) for voice communications (packet-based), andutilize the Mobile Internet Protocol (Mobile IP) for datacommunications. Integration of both the SIP-M and Mobile IP protocolsprovide greater flexibility to the roaming capabilities of the wirelesselectronic devices 10, 20, 30, 40. Mobile IP is an Internet EngineeringTask Force (IETF) standard protocol that runs on the network layer.Mobile IP permits a wireless PC, wireless PDA, or other mobile node tomove from one network link to another without interruptingcommunications. In an organization with W-LAN, a wireless notebook PCmay be physically moved from one building to another, into a newsub-network, without interrupting a file download or video stream, andwithout requiring the user to renew their network/IP address. SIP-M isan IETF standard protocol for IP communication that initiatesinformation-transfer sessions between applications. Unlike thetraditional telecommunications model that operates via a centralswitching element, SIP-M allows the control of services, like telephony,to be moved to the endpoints of a network in SIP-based PDA, notebook PC,Tablet PC clients or SIP-based mobile phones. SIP-M is flexible andextensible, and supports many different types of applications, includingvideo, telephony, messaging or instant messaging, and collaboration.However, any other suitable protocol or protocols may be utilized,though, for voice communication, data communication, or both.

[0017] A network address is assigned to the wireless electronic device20 once a wireless connection is established with the access point 193.If the wireless electronic device 20 should roam within the firstsub-network to another access point 191, its network address does notchange, but the wireless connection is simply disconnected from oneaccess point 193 and re-established with the other access point 191.Various quality of service (QoS) protocols or business rules may beimplemented to determine with which access point a wireless electronicdevice should establish a wireless connection. For example, signalstrength and available bandwidth may be factors in the considerationwhen a wireless electronic device is choosing from among a plurality ofaccess points of which it is within range. In one instance, it may bemore preferable to establish a wireless connection with an access pointhaving a poorer signal strength but has a greater availability ofbandwidth than compared to an access point having a stronger signal buthas 29 other users already connected.

[0018] When the wireless electronic device 20 roams out of range fromthe access points 191, 193 of a first sub-network and into a secondsub-network, the wireless connection with the access point 193 of thefirst sub-network is automatically disconnected, and seamlesslyre-established with a second access point 192 of the second sub-network.In an embodiment utilizing SIP-M for roaming, because the wirelesselectronic device 20 moved from one sub-network to another, a newnetwork address is assigned to the wireless electronic device 20. In anembodiment utilizing MobileIP for roaming, when the wireless electronicdevice 20 moves from one subnet to another, a new network address isassigned to the wireless electronic device.

[0019] The MCS server 140 manages a table of network addressescorresponding to, for example, telephone numbers/addresses (e.g., a PBXextension number) of each wireless electronic device 10, 20, 30, 40 onthe system 100. The table (e.g., see Table 1 below) may also include analias, or uniform resource locator (URL) address, e.g.,joe.doe@toshiba.com, corresponding to a telephone number or address of awireless electronic device 10, 20, 30, 40. When the wireless electronicdevice 20 roams from a first sub-network to a second sub-network, thenew network address (or alias/URL address) assigned to the wirelesselectronic device 20 at the second sub-network is updated in the table.The table permits routing of incoming telephone calls from the PSTN 102to the wireless electronic devices 10, 20, 30, 40, as well as telephonecalls from one wireless electronic device 10, 20, 30, 40 within thesystem 100 to another, either on the same sub-network or to anothersub-network. The table may be forwarded to the first node server 181 andthe second node server 182 as well so that a local copy is accessiblewithout having to cross the LAN backbone 110. The wireless electronicdevices 10, 20, 30, 40 may also make calls out to the PSTN 102 bydialing a conventional telephone number in the normal fashion, and thewireless electronic devices 10, 20, 30, 40 communicate with the PBXsystem 120 to make such outgoing calls. TABLE 1 Telephone AddressAlias/URL Address Network Address x3338 joe.doe@toshiba.com111.222.333.4 x3915 jane.doe@toshiba.com 111.222.333.8

[0020] The MCS server 140 preferably includes a simple networkmanagement protocol (SNMP) management system that performs usermanagement, server management, node server management, call featuremanagement, enterprise integration configuration, policy definition andenforcement, event monitoring, and general and specific reporting. SNMPagents may be preferably included with the first node server 181 and thesecond node server 182 to enable communication with the MCS server 140.The SNMP management system may be a Web-based system having a Web-basedinterface.

[0021] The MCS server 140, the first node server 181 the second nodeserver 182, and the wireless electronic devices 10, 20, 30, 49, may eachinclude a Quality of Service (QOS) module. The Quality of Service Modulemay ensure that data users only use a specific bandwidth (of the firstnode server 181 or the second node server 182 to the access points 192,193 to client device network 100), reserving the rest of the availablebandwidth for voice users. In embodiments of the invention not utilizingQoS, a user could start a voice call with good voice quality but thenthis voice quality would rapidly degrade if another user opens a largee-mail attachment.

[0022] By utilizing a fast IP address assigning protocol such as DRCP,the roaming of a wireless electronic device 20 from one sub-network toanother may be conducted seamlessly with a handoff time of approximately50-100 milliseconds (ms), or less. Accordingly, the handoff time is soshort that the disconnection from one sub-network and re-connection withanother is unnoticeable by users carrying on a voice conversation, forexample, with the wireless electronic device 10, 20, 30, 40. Thewireless electronic device 10, 20, 30, 40 is preferably any electronicdevice having telephony features (i.e., a speaker and a microphone), andmay be any suitable device, such as a PDA, a notebook PC, a tablet PC, acellular or mobile telephone (e.g., an IEEE 802.11b “Wi-Fi” IP telephone(an H.323 telephone)), an Internet Protocol (IP)-based Wirelesstelephone handset, a portable computer, etc. Moreover, the wirelesselectronic device 10, 20, 30, 40 is preferably capable of simultaneouscommunication of both voice and data over the wireless connection, evenwhile roaming from one sub-network to another.

[0023] Although the mobility communications system 100 illustrated inFIG. 1 shows a local area network (LAN) implementation, the system 100may be implemented even more broadly on a global/wide area network (WAN)scale, such that each sub-network may constitute a radio cell much likecellular telephone networks (and may even utilizing existing cellulartelephone network infrastructure), thus greatly expanding the wirelessfunctionality of the wireless electronic devices 10, 20, 30, 40 to allcorners of the world.

[0024] The wireless electronic devices 10, 20, 30, 40 may includeadvanced call features. Advanced call features may include call holding,transferring, forwarding, forwarding to voice mail, conference calling,etc. These are not typically associated with what non-telephone systemdevices can do, which is usually to just make and receive a call.Another advanced call feature is the ability to use internal four orfive digit calling capability to receive or transmit calls within thebusiness enterprise.

[0025] While the description above refers to particular embodiments ofthe present invention, it will be understood that many modifications maybe made without departing from the spirit thereof The accompanyingclaims are intended to cover such modifications as would fall within thetrue scope and spirit of the present invention. The presently disclosedembodiments are therefore to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims, rather than the foregoing description,and all changes that come within the meaning and range of equivalency ofthe claims are therefore intended to be embraced therein.

What is claimed is:
 1. A mobility communications system, comprising: alocal area network (LAN) backbone; a private branch exchange (PBX)system in communication with a public switched telephone network (PSTN);a gateway in communication with the PBX system and the LAN backbone; amobility communications system (MCS) server in communication with theLAN backbone; a first sub-network, including a first node server incommunication with the LAN backbone, and at least one first access pointin communication with the first node server; a second sub-network,including a second node server in communication with the LAN backbone,and at least one second access point in communication with the secondnode server; and a wireless electronic device having a wirelessconnection with the at least one first access point of the firstsub-network via a wireless protocol, wherein when the wirelesselectronic device roams from the first sub-network into the secondsub-network, the wireless connection with the first access point isautomatically disconnected and seamlessly re-connected with the at leastone second access point of the second sub-network.
 2. The mobilitycommunications system according to claim 1, wherein the gateway providesreal-time two-way communications between a PBX protocol of the PBXsystem and an Internet Protocol (IP) of the LAN backbone.
 3. Themobility communications system according to claim 1, wherein thewireless electronic device is selected from the group consisting of apersonal digital assistant (PDA), a notebook computer, a tabletcomputer, a cellular telephone, an Internet Protocol (IP)-based wirelesstelephone handset, and a portable computer.
 4. The mobilitycommunications system according to claim 1, wherein the wirelesselectronic device utilizes Mobile Internet Protocol (IP) for datacommunication and Session Initiated Protocol-Mobile (SIP-M) for voicecommunication.
 5. The mobility communications system according to claim1, wherein the wireless electronic device is adapted to simultaneouslycommunicate wirelessly data and voice.
 6. The mobility communicationssystem according to claim 1, wherein the MCS server assigns a networkaddress to the wireless electronic device when the wireless electronicdevice is in the first sub-network, and the MCS server assigns a newnetwork address to the wireless electronic device when the wirelesselectronic device roams from the first sub-network to the secondsub-network.
 7. The mobility communications system according to claim 1,wherein the MCS server assigns a network address to the wirelesselectronic device when the wireless electronic device is in the firstsub-network; and the MCS server assigns the network address to thewireless electronic device when the wireless electronic device roamsfrom the first sub-network to the second sub-network.
 8. The mobilitycommunications system according to claim 1, wherein the wirelesselectronic device includes a telephone address and a correspondingnetwork address.
 9. The mobility communications system according toclaim 8, wherein the network address is an alias address.
 10. Themobility communications system according to claim 9, wherein the aliasaddress is a uniform resource locator (URL) address.
 11. The mobilitycommunications system according to claim 8, wherein the network addressis an Internet Protocol (IP) address.
 12. The mobility communicationssystem according to claim 8, wherein the telephone address is a PBXextension telephone number.
 13. The mobility communication systemaccording to claim 1, wherein at least one of RADIUS and DIAMETERextensions are utilized for secure communication while roaming
 14. Themobility communication system according to claim 1, wherein the MCSserver further includes simple network management protocol (SNMP)management system that performs user management, server management, nodeserver management, call feature management, enterprise integrationconfiguration, policy definition and enforcement, event monitoring, andgeneral and specific reporting.
 15. The mobility communication systemaccording to claim 14, wherein the SNMP management system has a webinterface.
 16. The mobility communication system according to claim 14,wherein the SNMP management system is accessed from other SNMP-basedtools.
 17. The mobility communications system according to claim 1,wherein the MCS server, the first node server, the second node server,and the wireless communications device each include a Quality of Service(QOS) module to ensure that data users utilize a specific bandwidth. 18.The mobility communications system according to claim 1, wherein thewireless communications device includes advanced call features,including call hold, transfer, forward, forward to voice mail,conference call, and intra-enterprise call receiving/transmitting
 19. Amobility communications system, comprising: at least one first accesspoint in a first sub-network adapted to communicate wirelessly via awireless protocol; a mobility communications system (MCS) node server incommunication with the first access point; a wireless electronic devicehaving a wireless connection with the at least one first access pointvia the wireless protocol, the wireless electronic device including atelephone address and a network address; a mobility communicationssystem (MCS) server in communication with the at least one first accesspoint and a public switched telephone network (PSTN), the MCS serverincluding a table of the network address of the wireless electronicdevice corresponding to the telephone address of the wireless electronicdevice, wherein when the wireless electronic device roams from the firstsub-network to a second sub-network, the wireless connection with the atleast one first access point is automatically disconnected andseamlessly re-connected with at least one second access point of thesecond sub-network. 20 The mobility communications system of claim 19,wherein the wireless electronic device is assigned a new network addressat the second sub-network. 21 The mobility communications system ofclaim 19, wherein the wireless electronic device is assigned the networkaddress at the second sub-network.
 22. The mobility communicationssystem of claim 19, wherein the wireless connection with the at leastone first access point is automatically disconnected and seamlesslyre-connected with the at least one second access point of the secondsub-network based on variable business rules, including as signalstrength, quality of service, and cost.
 23. The mobility communicationssystem according to claim 19, wherein the MCS server assigns the networkaddress to the wireless electronic device when the wireless electronicdevice is in the first sub-network, and the MCS server assigns the newnetwork address to the wireless electronic device when the wirelesselectronic device roam from the first sub-network to the secondsub-network.
 24. The mobility communications system according to claim19, wherein the network address is an alias address.
 25. The mobilitycommunications system according to claim 24, wherein the alias addressis a uniform resource locator (URL) address.
 26. The mobilitycommunications system according to claim 19, wherein the network addressis an Internet Protocol (IP) address.
 27. The mobility communicationssystem according to claim 19, wherein the wireless electronic device isselected from the group consisting of a personal digital assistant(PDA), a notebook computer, a tablet computer, a cellular telephone, anInternet Protocol (IP)-based wireless telephone handset, and a portablecomputer.
 28. The mobility communications system according to claim 19,wherein the telephone address is a private branch exchange (PBX)extension telephone number.
 29. The mobility communications systemaccording to claim 19, wherein the wireless electronic device utilizesMobile Internet Protocol (IP) for data communication and SessionInitiated Protocol-Mobile (SIP-M) for voice communication.
 30. Themobility communications system according to claim 19, wherein thewireless electronic device utilizes Mobile Internet Protocol (IP) forboth data communications and for voice communications.
 31. The mobilitycommunications system according to claim 19 wherein the wirelesselectronic device is adapted to simultaneously communicate wirelesslydata and voice.
 32. The mobility communications system according toclaim 19, further including a private branch exchange (PBX) system incommunication with the public switched telephone network (PSTN) and themobility communications system (MCS) server.
 33. A method of wirelesscommunication, comprising: establishing a wireless connection with atleast one first access point via a wireless protocol in a firstsub-network by a wireless electronic device; assigning a network addressto the wireless electronic device having a telephone address; roamingfrom the first sub-network to a second sub-network; disconnectingautomatically the wireless connection with the at least one first accesspoint; establishing seamlessly the wireless connection with at least onesecond access point in the second sub-network; and assigning a newnetwork address to the wireless electronic device at the secondsub-network.
 34. The method according to claim 33, further includingupdating a table having the network address of the wireless electronicdevice with the new network address corresponding to the telephoneaddress of the wireless electronic device.
 35. The method according toclaim 33, wherein the wireless electronic device is selected from thegroup consisting of a personal digital assistant (PDA), a notebookcomputer, a tablet computer, a cellular telephone, an Internet Protocol(IP)-based wireless telephone handset, and a portable computer.
 36. Themethod according to claim 33, further including utilizing MobileInternet Protocol (IP) for data communication and utilizing SessionInitiated Protocol-Mobile (SIP-M) for voice communication.
 37. Themethod according to claim 33, wherein the telephone address is a privatebranch exchange (PBX) extension telephone number.
 38. The methodaccording to claim 33, further including communicating simultaneouslyvoice data and non-voice data over the wireless connection.
 39. Aprogram code storage device, comprising: a machine-readable storagemedium; and machine-readable program code, stored on themachine-readable storage medium, having instructions to establish awireless connection with at least one first access point via a wirelessprotocol in a first sub-network; receive a network address correspondingto a telephone address; disconnect automatically the wireless connectionwith the at least one first access point when a wireless electronicdevice roams from the first sub-network to a second sub-network;establish seamlessly the wireless connection with the at least onesecond access point in the second sub-network; and receive a new networkaddress at the second sub-network.
 40. The program code storage deviceaccording to claim 39, wherein the machine-readable program code furtherincludes instructions to update a table having the network address withthe new network address corresponding to the telephone address.
 41. Theprogram code storage device according to claim 39, wherein the wirelesselectronic device is selected from the group consisting of a personaldigital assistant (PDA), a notebook computer, a tablet computer, acellular telephone, an Internet Protocol (IP)-based wireless telephonehandset, and a portable computer.
 42. The program code storage deviceaccording to claim 39, wherein the machine-readable program code furtherincludes instructions to utilize Mobile Internet Protocol (IP) for datacommunication and to utilize Session Initiated Protocol-Mobile (SIP-M)for voice communication.
 43. The program code storage device accordingto claim 39, wherein the telephone address is a private branch exchange(PBX) extension telephone number.
 44. The program code storage deviceaccording to claim 39, wherein the machine-readable program code furtherincludes instructions to communicate simultaneously voice data andnon-voice data over the wireless connection.